Registration Dossier

Environmental fate & pathways

Biodegradation in water: screening tests

Administrative data

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2019

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
liquid

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge (adaptation not specified)
Details on inoculum:
Inoculum used in this study was collected from 12 sites in Korea including 5 rivers(Gangjeong, Mulgeum, Gurye, Gapcheon, Paldang), 4 domestic sewage treatment plants(Dalseo, Gumi, Busan, Asan) and 3 industrial wastewater treatment plants(Dalseo, Yeosu, Tancheon). Fresh samples collected from these sites were incubated for over one month and the activated sludge greater than 10^7 cells/mL was used in this test.
Duration of test (contact time):
<= 28 d
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
This study is to screen the chemical for ready biodegradability in an aerobic aqueous medium. The method is applicable to the organic test substance of non-volatile, Cwater : Cair ≥ 1, with no inhibitory to microorganism, and with no reaction by the CO2 absorbent.
The oxygen uptake of test substance in a mineral medium is measured automatically over a period of 28 days in darkened and enclosed respirometer at 25 ± 1℃. If the biodegradability is calculated by the percentage oxygen uptake of theoretical uptake (ThOD) of the test substance is 60% or more, the test substance could be concluded as a readily degradable substance by microorganisms in the aquatic environment.
Reference substance
Reference substance:
aniline

Results and discussion

% Degradation
Key result
Parameter:
% degradation (O2 consumption)
Value:
1.1
Sampling time:
28 d
Remarks on result:
other:
Remarks:
not readily biodegrable
Details on results:
The percentage biodegradations of the test substance was observed by BOD measurement was calculated with a range of 0.0 ~ 3.3% and the average percentage biodegradation was calculated to be 1.1% for 28 days. Therefore, these results indicate that the test substance is not biodegradable in aqueous condition.

BOD5 / COD results

Results with reference substance:
The percentage biodegradations of the reference compound, aniline, observed by BOD measurement were 67.0% after 7 days and 71.6% after 14 days.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
not readily biodegradable
Conclusions:
The test substance could not be concluded as a readily degradable substance by microorganisms in the aquatic environment because the percentage biodegradation of the test substance by BOD measurement was less than pass level for ready biodegradability (60%) specified in the OECD guideline.